1. Field of the Invention
The present invention relates to a substrate transfer apparatus that is used in a wet developing process for manufacturing a substrate of a flat display device. More particularly, the present invention relates to a substrate transfer apparatus that is designed to provide an inclined transfer function that improves liquid saving efficiency of a process solution (developing solution) during the transfer of the substrate.
2. Description of the Related Art
A photolithography process is generally used to form a circuit pattern on a substrate of a flat display device. The photolithography process includes a wet developing process for developing an exposed resist layer on the substrate using a developing solution.
The wet developing process includes a process for applying the developing solution to the resist layer of the exposed substrate, a process for cleaning the substrate, and a process for drying the substrate. These processes are sequentially performed during the transfer of the substrate from a first side to a second side in a chamber by a transfer apparatus.
The transfer apparatus is generally provided in the form of a roller conveyer type that transfers the substrate by rotation of transfer rollers and has an inclined transfer section for liquid saving to improve recovery and recycling efficiencies of the developing solution during the transfer of the substrate.
Korean laid-open patent No. 10-2007-0093343 (filed in 2007) discloses a substrate treatment apparatus having an inclined transfer section for saving the liquid.
The substrate treatment apparatus of the laid-open patent has an inclined transfer section between developing and cleaning sections of an entire substrate transfer section. The inclined transfer section is designed such that, when the substrate comes out of the developing section, the substrate is transferred along an upwardly inclined transfer section and, when the substrate goes into the cleaning section, the substrate is transferred along a downwardly inclined transfer section.
When the inclined transfer section for saving the liquid is defined in the entire transfer section, remaining developing solution on the substrate runs off as the substrate is transferred along the upwardly inclined transfer section, thereby being recovered to a developing chamber.
Therefore, the inclined transfer section increases the recovery rate of the developing solution during die developing process and prevents the cleaning solution from being polluted by excessive flow of the developing solution into the cleaning chamber.
However, since the substrate treatment apparatus disclosed in the laid-open patent No. 10-2007-0093343 is structured such that transfer rollers located at the inclined transfer section are integrally coupled to the chamber, the following problems may occur during the developing process.
For example, since an inclined angle and connection state of the inclined transfer section cannot be properly adjusted in response to the size of the substrate and the working environment (developing speed), working compatibility is deteriorated.
Particularly, when the inclined angle of the inclined transfer section is not properly adjusted in response to the size of the substrate and the working environment, it is difficult to expect a sufficient liquid saving effect during the inclined transfer of the substrate.
Hence, the recovery rate of the developing solution is deteriorated and thus the consumption of the developing solution increases. In addition, since an excessive amount of the developing solution is mixed with the cleaning solution, the recycling rate of the cleaning solution is significantly reduced.
When the substrate goes into or comes out of the inclined transfer section, a front end of the substrate may be easily put between the rollers or contact the rollers, and thus the substrate may be damaged or its position may be changed. This causes the substrate to be transferred in an abnormal state where the position of the substrate changes or the substrate is damaged.
When the substrate is abnormally transferred as described above, the cleaning solution or drying air is non-uniformly supplied to a treating surface of the substrate during the cleaning process or drying process, and thus the cleaning and drying qualities may be deteriorated.
The above information disclosed in this Background section is only for enhancement of understanding of the background of die invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.